1. Field of the Invention
The present invention relates to a photosensor and a method of manufacturing the same.
2. Description of the Related Art
A photosensor having a P-I-N structure is a semiconductor device which converts an optical signal into an electrical signal. In a photosensor having the P-I-N structure, a negative voltage may be applied to a P-type doped region, and a positive voltage may be applied to an N-type doped region. In this state, if light is incident on the photosensor, the energy of the incident light causes electrons and holes to be generated in an intrinsic region or causes electrons and holes to be generated in an N/P-type doped region, and then to diffuse to the intrinsic region. Consequently, electric current flows through the photosensor due to a reverse electric field of the intrinsic region. In this regard, a larger amount of light or higher energy causes more current to flow through the photosensor, and transistors output electrical signals according to the amount of current, thereby operating the photosensor.
To form the P-I-N structure, two rounds of doping process (that is, P-type doping and N-type doping) are required, which complicates the manufacturing process and raises manufacturing costs.